North Korea's hard-line communist regime is using old US-made target drones to develop unmanned attack aircraft, South Korea intelligence sources said Sunday.

"North Korea recently bought several US MQM-107D Streakers from a Middle Eastern nation that appears to be Syria, and is developing unmanned attack aircraft based on them," the South's Yonhap news agency quoted an intelligence source as saying.

Its powerful military placed explosives on the drones in a number of tests, but was yet to master the technology, the report said....